I am running FreeBSD 8-0-Stable and am running the latest NVIDIA. Since I have moved to 64Bit FreeBSD and NVIDIA, I have had issues with VirtualBox freezing. However, I was able to downgrade my video card and run the NV driver today and found that I have no freeze issues with Virtualbox anymore. This has been across multiple versions of Virtualbox and from kernel sources compiled since the NVIDIA driver for 64bit FreeBSD was released.

I'm attaching a bug report with the NVIDIA kernel module loaded but I am currently running the NV driver. Please let me know what information you need from this. I believe that others have also posted of this issue. This is the last freeze issue I am seeing now with the 64bit NVIDIA driver for FreeBSD.